Re: Hum, Ground Loops and Safety


"Brian Running" <brunning@xxxxxxxxxxxxxxxxx> wrote in message
news:OrOak.16051$Ri.5243@xxxxxxxxxxxxxxxxxxxxxxx
Electricity is a little bit like water, enough so that we can use water as
an analogy.


From the viewpoint of a person who has been an electronic technician for 30+
years, a very excellent analogy, and quite inclusive of the imperfections
that are common in building wiring. I worked in broadcast radio and TV for a
number of years also - on the audio side, there were two accepted methods
for reducing the effect of ground loops that were coupled in from the AC
power wiring - one was the isolation method (typified in the old days by
balanced to balanced transformers so that audio neutral could be decoupled
from power ground, a bit later by such devices as optoisolators - photocell
and LED) and brute force grounding - using very heavy materials such as 2x2
inch copper busbar to reduce ground resistance as much as possible.

Jim Cason
Promised LAN Computing, Inc.


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